
FastFlow: Fasting Tracker
Fasting with live biometrics
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Free
In-App Purchases
About
FastFlow turns intermittent fasting into a guided, personalized journey — and it reads your Garmin's biometrics in real time so you can actually see your fast working.
Connect a compatible Garmin watch and FastFlow maps your fast through six metabolic stages — Fed, Clearing, Shifting, Burning, Cleansing, Renewing — using your live heart rate, HRV, Body Battery, and stress. Instead of a plain timer, you see what's happening inside your body, and what to do at each stage.
WHY FASTFLOW
- Live biometrics, not just a clock. Your Garmin data drives the ring, so every stage is grounded in what your body is actually doing.
- Know what to do, hour by hour. Each stage suggests the right activities — sleep through the early hours, deep work and fasted training in Burning, rest in the long stages.
- A smart end-of-fast review. Log how the fast went in two taps; FastFlow reviews it against your own baseline, entirely on your device.
- Break your fast the right way. A guided, step-by-step refeeding flow with gentle food suggestions — plus a shop for break-fast staples like bone broth and electrolytes.
- Build the habit. Streaks, a color-coded calendar of your fasts, and per-stage insight.
LIVE ACTIVITY + DYNAMIC ISLAND
Track your fast from the Lock Screen and Dynamic Island — the stage and elapsed time stay current at a glance.
PRIVATE BY DESIGN
FastFlow has no account. Your fasting and health data is processed on your device and stored in your own private iCloud. We don't collect, sell, or share it.
REQUIRES A GARMIN
Live biometric sync requires a compatible Garmin watch with the FastFlow watch app (available on the Garmin Connect IQ Store). You can also use FastFlow phone-only: start/stop fasts, follow the stage journey, log break-fasts, and keep your history.
FASTFLOW PREMIUM
A subscription unlocks live Garmin biometric sync, full history and insights, and Live Activity.
- Monthly and annual plans, with a free trial.
- Payment is charged to your Apple ID at confirmation of purchase.
- Subscriptions renew automatically unless turned off at least 24 hours before the end of the period.
- Manage or cancel anytime in your App Store account settings.
- Terms: https://fastflowapp.com/terms
- Privacy: https://fastflowapp.com/privacy
FastFlow is a general wellness and fasting-tracking app. It is not a medical device
and does not provide medical advice, diagnosis, or treatment. Any biometric data
shown comes from your own consumer fitness wearable and is for general wellness
information only. Always consult your doctor before making any medical decisions,
starting a fast, or changing your health routine.
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What's New in FastFlow
1.0
July 16, 2026
Subscription plans
Annual
1 year subscription
$39.991 Year







